Process for increasing the amino-acid content in cereals

ABSTRACT

There is provided an improvement in the process for increasing the amino acid content of cereals by contacting with an aqueous solution of at least one amino acid to cause absorption of the amino acid into the cereal. The improvement resides in first increasing the water content of the cereal prior to contacting the cereal with the solution of at least one amino acid, whereby an increased absorption of the amino acid is obtained.

United States Patent Inventor Gerardus A. Geurts Geleen, NetherlandsAppl. No. 781,988

Filed Dec. 6, 1968 Patented Nov. 2, 1971 Assignee Stamicarbon N. V.Heelen Netherlands Priority Dec. 7, 1967 Netherlands PROCESS FORINCREASING THE AMINO-ACID CONTENT IN CEREALS k, 11,80 PS [56] ReferencesCited UNITED STATES PATENTS 3,157,514 11/1964 Gorozpe 99/80 OTHERREFERENCES Matz, Samuel A., The chemistry and Technology of Cereals asFood and Feed," Westport, Conn. 1959, page 631. TX 545M36 PrimaryExaminer- Lionel M. Shapiro Assistant Examiner-James R. HoffmanAttorney-Cushman, Darby & Cushman ABSTRACT: There is provided animprovement in the process for increasing the amino acid content ofcereals by contacting with an aqueous solution of at least one aminoacid to cause absorption of the amino acid into the cereal. Theimprovement resides in first increasing the water content of the cerealprior to contacting the cereal with the solution of at least one aminoacid, whereby an increased absorption of the amino acid is obtained.

PROCESS FOR INCREASING THE AMINO-ACID CONTENT IN CEREALS Detaileddescription of the invention This invention relates to an improvement ina process for increasing the amino-acid content of cereals, wherein acereal is contacted with an aqueous solution containing one or .moreamino acids for a period of time sufficient that theamino acid isabsorbed by the cereal. This application, being assigned to the sameassignees as the present application, reference.

According to the process described in that application, the amino-acidcontent of cereals may be increased with substantial preservation of thegranular character of the cereal. According to that invention, a cerealis contacted with an aqueous solution of at least one amino acid, e.g. a3 to 40 percent by weight solution, for a period of time sufficient tocause the amino acid to be absorbed by the cereal and substantiallyincrease the amino-acid content thereof. Typically, the contact time isbetween and 45 minutes at 40 to 85 C. witha resulting amino-acid contentof the cereal between about 600 percent and 3300 percent of thenaturalamino-acid content.

Such a process is, of course, quite important for increasing thenutritional value of cereals and represents a very efficient way ofenriching" products which are normally relatively low in amino acids,e.g. bread and cakes. However, it would be most desirable to furtherincrease the amino-acid contentof cereals, especially where highamino-acid contents are important in special dietary problems. Further,where a cereal with a highamino-acid content can be obtained, thesecereals may be blended in relatively small proportions withuntreatednatural cereals to provide any desired final amino-acid content withoutthe necessity of treating all or substantially all of the cereal inorder to obtain a relatively high average aminoacid content.

Accordingly, it is an object of the present invention to provide animproved process for increasing the amino-acid content of cerealswherein exceptionally high amino-acid contents may be obtained. It is afurther object to provide cereals with heretofore unobtainableamino-acid contents. Other objects will be apparent from the followingdisclosure and claims.

Briefly stated, it has now been found that in the treatment of a cerealwith an aqueous solution of at least one amino acid, a considerablyhigher amino-acid content may be obtained, with preservation of thegranular character of the cereal, by contacting the cereal with waterfor a period of time sufficient to increase the water content of thecereal and thereafter contacting the cereal having an increased watercontent with the solution of at least one amino acid.

For purposes of the present specification and claims, the term "aminoacid is intended to embrace the so-called essential amino acids and thederivatives thereof (See Condensed Chemical Dictionary, 6th Ed.) ofwhich lysine, methionine and threonine are examples. Often convenientuse is made of the derivatives of the amino acids and these knownderivatives are also intended to be embraced by the mentioned terms.

Similarly, the term cereal is intended to embrace the group of naturalgrains used for human and animal consumption and include wheat, rice,rye and maize. Accordingly, it should be understood that the particularamino acid and cereal is not critical to the present process.

The increase of the water content of the cereal is not altogethercritical, but in order to effect a substantial increase in the amount ofamino acid absorbed, the increase in water content, expressed as weightpercent increase over the weight of the natural cereal, should be atleast 3 percent, preferably at least 4 percent and especially at least10 percent. The increase in water content of the cereal is important,since the amount of amino acid absorbed by the cereal is dependentthereon, as well as upon the cereal.

For example, in the treatment of wheat with an aqueous solutioncontaining L-lysine monohydrochloride, the L-lysine monohydrochloridecontent in the wheat may be increased to rotating in oppositedirections,between about 8 percent by weight, if the wheat contains an additional30 percent by weight of water (calculated with respect to the weight ofwheat containing its natural water content).

As a furtherfeature of the invention, it has been found that the amountof amino acid absorbed can be further increased if the cereal which hasan increased water content is broken (as hereinafter defined) beforebeing treated with the solution of an amino acid. For example, if thesame wheat mentioned above (natural-water content of about l4 percent isincreased in .water content by 30 percent with respect to the weight ofthe wheat and the wheat grains are then broken, the treatment with anaqueous solution of L-lysine monohydrochloride, will produce a L-lysinemonohydrochloride content of the wheat of about 12 percent by weight, asopposed to the 8 percent by weight of the wheat treated with unbrokengrains. Preferably, the cereal isfirs increased in water content andsubsequently broken, because this facilitates the breakingprocedure,-but

the reverse of the steps may be practiced.

The terms broken grains are defined as grains which have had the husksthereof cracked, but with substantial preservation of the granularcharacter of the cereal. Thehusk may be broken by meansknown to the artsuch as subjecting the grains to a light pressure, e.g. between tworubber-lined rollers rotating discs, by fluid blasts and by vigoroustumbling.

The present improvement is, indeed, quite surprising, since from atheoretical point of view, it wouldbe assumed that an increased watercontent of the cereal to be treated with the amino-acid solution wouldhave an adverse effect or at least no effect at all on the amount ofamino acids absorbed by the cereal. The present improved result isespecially surprisingin view of the fact that the process of theaforementioned appli cation provides an excess of water during thetreatment with the amino-acid solution.

In this latter. regard, even if .cereal with the natural water contentis subjected to a prolonged treatment. e.g. 10 hours or more, asdescribed in the aforementioned application. the amount of amino acidsabsorbed by the cereal will be much smaller than that absorbed by thecereal with an increased water content in a much shorter time, as taughtby the present invention.

The present improved process has an important advantage in that itpermits the treating a smaller portion of a cereal with the aqueoussolution containing one or more amino acids in order to obtain thedesired average amino-acid content in the total amount of the cerealupon mixing of the treated portion with an untreated portion. it furtherallows the production of cereals with heretofore unobtainably high aminoacid contents.

Generally speaking, a sufficient increase in water content of the cerealto be treated according to the invention may be obtained by contacting,e.g. soaking, spraying, dipping, etc., the water with the cereal for arelatively short time such as from it to 6 hours, e.g. for 1-4 hours.

While the temperature of the water for increasing the water content ofthe cereal is not critical, elevated temperatures are preferred sincethe absorption of water by the cereal takes place more rapidly at highertemperatures. The water temperature is therefore suitably up to theboiling point of water, e.g. between 40 and 70 C. However, if desired,the cereal may also be contacted with steam (preferably low pressure.e.g. up to 20 p.s.i.g., saturated steam) instead of with water Since asnoted above, a higher amino-acid content of the cereal can be obtainedwith increasing amount of water which has been absorbed by the cereal,by controlling the amount of water absorbed by the cereal, i.e.controlling the time and temperature of the water contacting step, theamount of amino acid absorbed may also be controlled. l

However, valuable results may be obtained over a relatively wide rangeof percent increases in water content of the cereal over cereal with thewater content of the natural cereal, e.g. from about 3 percent to 55percent, especially 4 percent to 45 percent. of course, the particularamount of water absorbed will depend upon the particular cereal beingtreated. For example, the water content of wheat is preferably increasedby an amount corresponding to a 4-30 percent by weight increase of watercontent with respect to the wheat with a natural water content. In thecase of maize, the percentage increase in water content preferablyvaries from to 45 percent by weight.

Of course, after the cereal of increased water content is treated withthe aqueous solution of one or more amino acids, the cereal may bedried, e.g. at up to 85 C., especially between 40 and 70 C., to reducethe moisture content to any desired level, e.g. the natural level.

The improved process according to the invention will be furtherillustrated by the following examples, but it is to be understood thatthe invention is not limited to the examples, but is fully applicable tothe foregoing disclosure.

Example 1 100 g. of wheat grains (natural water content 14 percent byweight; L-lysine content 0.2 percent by weight) were contacted bysoaking with 200 g. of water at 60 C. for 3% hours. The grains absorbed30 g. of water during that period (the increased water contentpercentage of the soaked wheat with respect to the wheat with a naturalwater content amounts to 30 percent by weight). The grains wereseparated off by filtration and subsequently contacted with an aqueoussolution containing 30 percent by weight of L-lysine monohydrochlorideat 60 C. for 4 hours.

The grains were filtered off, washed with flowing water, and dried in anoven at 60 C. to a water content of percent by weight. The L-lysinemonohydrochloride content of the dried wheat grains was determined to be8 percent by weight. As a comparison, wheat grains (natural watercontent of 14 percent by weight) were treated in the same manner asabove but without the water soaking step. The L-lysine monohydrochloridecontent of the dried wheat grains was determined to be only 3.8 percentby weight.

Example 2 100 g. of wheat grains were contacted by soaking with 220 g.of water at 60 C. for 3 hours. The water which had not been absorbed wasremoved by filtration, after which the grains were broken by passing thewheat grains between two rubberlined rollers rotating in oppositedirections (shortest distance between the rollers: 2 millimeters;diameter of the rollers: 8 centimeters). The amount of water absorbed bythe grains amounted to 28 g.

Subsequently, the broken grains were contacted by soaking with anaqueous solution containing 25 percent by weight of L-lysinemonohydrochloride at C. for 3% hours.

The grains were filtered off, washed with flowing water, and

dried at 55 C. in an oven. The dried wheat grains contain 1 1.8 percentby weight of L-lysine monohydrochloride and 14 percent by weight ofwater.

Example 3 g. of maize grains (natural water content 12.5 percent byweight; L-lysine content 0.3 percent by weight), were contacted bysoaking with g. of water at 55 C. for 3% hours. The maize grains, whichhave absorbed 40 g. of water in the treatment, were separated of? byfiltration and subsequently treated with an aqueous solution containing30 percent by weight of L-lysine monohydrochloride at 60 C. for 3 hours.Thereafter, the grains were filtered off, washed with flowing water, anddried at 60 C. in an oven. The L-lysine monohydrochloride content of thedried maize grains was 9.5 percent by weight, while the water contentwas 13 percent by weight.

As can be seen from the above examples, cereals with exceptional highincreases in the amino-acid content may be obtained. For example acontent of lysine (which is an essential amino acid) of oyer 1100percent of the original lysine content may be obtained in the treatingof unbroken cereals. In

the treating of broken cereals a lysine content may be obtained whichamounts to over 3400 percent of the original lysine content. Heretoforesuch increases in amino-acid contents were not obtainable.

What is claimed:

1. A process for increasing the amino acid content of cereals consistingessentially of a. contacting cereal grain with water at a temperature offrom about 40 C. to about 70 C. for a period of time sufficient toincrease the water content of the cereal by 4 to 5 5 percent by weightof the cereal,

b. transferring said cereal grain, containing said increased watercontent, to an aqueous solution of at least one amino acid having atemperature between about 40 C. and about 85 C. and

c. contacting said cereal with said aqueous amino-acid solution for asufficient time to absorb a substantial amount of the amino acid.

2. Process according to claim number 1 in which the grains of the cerealare broken.

3. Process according to claim 2, in which the cereal is contacted withwater to increase the water content thereof prior to breaking the grainsof the cereal.

4. A process according to claim 1, in which the cereal is wheat and thewater content of the wheat is increased by 4 to 30 percent by weight ofthe wheat.

5. A process according to claim 1 in which the cereal is maize and thewater content of the maize is increased by 10 to 45 percent by weight ofthe maize.

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2. Process according to claim number 1 in which the grains of the cerealare broken.
 3. Process according to claim 2, in which the cereal iscontacted with water to increase the water content thereof prior tobreaking the grains of the cereal.
 4. A process according to claim 1, inwhich the cereal is wheat and the water content of the wheat isincreased by 4 to 30 percent by weight of the wheat.
 5. A processaccording to claim 1 in which the cereal is maize and the water contentof the maize is increased by 10 to 45 percent by weight of the maize.